1. Field of the invention
The present invention generally relates to an apparatus for connecting wiring on a steering wheel to a wiring on a steering column for use in an automotive vehicle, and especially relates to an apparatus which is capable of indicating a number of turns of the steering wheel.
2. Description of the related art
Conventionally, there are various types of the above-mentioned apparatus in practical use. Generally, such an apparatus has a coil-shaped cable member of a flexible material, in which a plurality of electrically conductive wire rods are arranged. These types of apparatuses have been disclosed, for example, in Japanese Laid-open Utility Model Publication No. 53-118243 (1978) and Japanese Laid-open Patent Publication No. 57-66045 (1982).
In the conventional type of apparatus as described above, the cable member is accommodated in a case which is normally located under a steering wheel and comprises a stationary casing fitted to the side of a steering column and a rotatable case member fitted to the side of the steering wheel. One end of the cable member is fixed at the stationary casing, and the other end is fixed at the rotatable case member. When assembling the apparatus and mounting it between the steering wheel and column, it is necessary to maintain a neutral condition of the coil-shaped cable member, since the apparatus is being mounted thereto.
In an apparatus having the above-mentioned structure, however, there is a disadvantage that there is no way to visually confirm whether or not the coil-shaped cable member returns to its neutral shape when the steering wheel is turned to its neutral position, since it is normally impossible to look at the inside of the case from its outside. That is, there is no way to confirm visually whether or not a neutral position of the steering wheel is in conformity with that of the coil-shaped cable member in the case. In addition to the above, even though it is possible to look at the interior of the case through a window or a transparent wall of the case, it is difficult to confirm the neutral condition of the coil-shaped cable member without any helpful means because of a large number of coils. Therefore, even if the apparatus is initially arranged with a correct relationship between the two, it is difficult to mount the apparatus with the correct relationship, i.e., under the condition of keeping the coil-shaped cable member neutral, to its place in the automotive vehicle again after the apparatus is dismounted for any reason.
If the apparatus is connected to the steering wheel and there is no adjustment between the two such that the cable member remains biased, there is a possibility that the electrical connection between the steering wheel side and the steering column side may be interrupted with the rotation of the steering wheel.